package org.apache.lucene.document;

import java.util.Set;

/**
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Declare what fields to load normally and what fields to load lazily
 * 
 */
public class SetBasedFieldSelector implements FieldSelector {

	private Set fieldsToLoad;
	private Set lazyFieldsToLoad;

	/**
	 * Pass in the Set of {@link Field} names to load and the Set of
	 * {@link Field} names to load lazily. If both are null, the Document will
	 * not have any {@link Field} on it.
	 * 
	 * @param fieldsToLoad
	 *            A Set of {@link String} field names to load. May be empty, but
	 *            not null
	 * @param lazyFieldsToLoad
	 *            A Set of {@link String} field names to load lazily. May be
	 *            empty, but not null
	 */
	public SetBasedFieldSelector(Set fieldsToLoad, Set lazyFieldsToLoad) {
		this.fieldsToLoad = fieldsToLoad;
		this.lazyFieldsToLoad = lazyFieldsToLoad;
	}

	/**
	 * Indicate whether to load the field with the given name or not. If the
	 * {@link Field#name()} is not in either of the initializing Sets, then
	 * {@link org.apache.lucene.document.FieldSelectorResult#NO_LOAD} is
	 * returned. If a Field name is in both <code>fieldsToLoad</code> and
	 * <code>lazyFieldsToLoad</code>, lazy has precedence.
	 * 
	 * @param fieldName
	 *            The {@link Field} name to check
	 * @return The {@link FieldSelectorResult}
	 */
	public FieldSelectorResult accept(String fieldName) {
		FieldSelectorResult result = FieldSelectorResult.NO_LOAD;
		if (fieldsToLoad.contains(fieldName) == true) {
			result = FieldSelectorResult.LOAD;
		}
		if (lazyFieldsToLoad.contains(fieldName) == true) {
			result = FieldSelectorResult.LAZY_LOAD;
		}
		return result;
	}
}